1. Field Of The Invention
The invention relates to novel polyester diols that are reactive with polyisocyanates and polymerizable olefinically unsaturated monomers to produce tough polyurethane/vinyl polymer copolymers. The invention also relates to novel compositions containing said polyester diols, to said polyurethane/vinyl polymer copolymers, and to novel methods for making them.
2. Description Of The Prior Art
Polyester polyols have been and are currently being used in the production of polyurethane products. In addition, as explained more specifically hereinafter, such polyester polyols have in certain cases been reacted with polyisocyanates and olefinically unsaturated monomers but in no case in the prior art has there been any disclosure or suggestion of preparing polyester diols of the type provided by this invention or which are capable of providing the polyurethane/vinyl polymer copolymers produced by the present invention.
Japanese Publication No. JA-49109496, published Oct. 17, 1974, discloses compositions made from unsaturated polyester polyols, polyisocyanates and olefinically unsaturated monomers, such as styrene. The unsaturated polyester polyol disclosed by this publication, however, is produced from olefinically unsaturated dibasic acids or anhydrides and does not teach or suggest polyester diols made from aliphatically saturated and olefinically unsaturated dicarboxylic acids. The absence of aliphatically saturated dicarboxylic acids or anhydrides results in final resin compositions which have inferior physical properties, such as elongation and brittleness as compared to the final resin products made in accordance with the present invention. Furthermore, this publication is dedicated to ensuring that vinyl polymerization occurs before or during the early stages of polyurethane-formation and, to force this result, requires the use of two vinyl polymerization catalysts, azobisisobutyronitrile and a peroxide or peroxide-generating catalyst.
U.S. Pat. No. 3,008,917 discloses the preparation of polyisocyanate-polyester adducts which are subsequently reacted with vinyl monomer, such as styrene, to form coatings, castings, laminates, adhesives, etc., which, however, have inferior physical properties, e.g., impact resistance, compared to compositions of this invention. In addition, this patent fails to disclose any olefinically unsaturated polyesters in which the ratio of glycol moieties to dicarboxylic acid moieties is 1.75:1 or more. Specifically, in col. 2, the formula shown on line 20 contains usually three or more repeating units which results in a ratio of four glycol moieties to three dicarboxylic acid moieties representing approximately 331/3% excess glycol or 1.331/3 glycol moieties per dicarboxylic acid moiety. Also, column 4, lines 20 through 28 define a maximum of 40% excess of the glycol moiety which is not near to a 2:1 ratio. This patent teaches the need to use hot styrene for the purpose of dissolving the high molecular weight polyisocyanate polyester adduct (col. 5, lines 6-9). This causes additional handling and safety difficulties as well as requires the presence of a gelation inhibitor specified by Park et al during the difficult mixing stage. Another distinction over the Park et al patent is the necessity in Park et al of using large amounts of unreacted isocyanate groups (col. 7, line 73 through col. 8, line 5).
U.S. Pat. Nos. 2,915,493; 2,879,248 and 3,047,530 and British Pat. No. 744,027 disclose mixtures of polyisocyanate-modified unsaturated polyesters and vinyl monomers such as styrene. These patents, however, fail to disclose any polyester diol in which the mole ratio of glycol moieties to dicarboxylic acid moieties is 1.75 or more.
German Pat. No. 956,720, issued 1957, discloses the preparation of compositions from an olefinically unsaturated polyester polyol, an olefinically unsaturated monomer and a polyisocyanate, but fails to disclose the use of combinations of a branched glycol or its equivalent and a linear glycol or its equivalent as specified in the present invention. In addition, the German patent fails to disclose or suggest a ratio of polyol moieties to polycarboxylic acid moiety of 1.75:1 or more. As a consequence, the resin compositions produced by the German patent possess physical properties that are inferior to those provided by applicants' resin compositions.
French Pat. No. 1,477,822 discloses molded polyester resins intended for the manufacture of molded products or surface coating compositions relying on humidity-curing in order to produce a hard solid product. The patent, however, does not disclose or suggest unsaturated polyester resins which are made from combinations of saturated and unsaturated dicarboxylic acids or anhydrides and branched and linear glycols, such as are described in the present invention. In addition, the unsaturated polyester compositions of the French patent are reacted with a large stoichiometric excess of polyisocyanate which results in a prepolymer having a large proportion of free NCO groups and which is designed for use in a humidity-cured product. Furthermore, the unsaturated polyester-polyisocyanate prepolymer, if not made with an excess of polyisocyanate, would form solid, or at least highly viscous, and difficult-to-dissolve materials which could not be combined with styrene except with extreme difficulty, if at all. There is no disclosure or suggestion of the unsaturated polyester diols disclosed and claimed herein nor of the polymerizable compositions containing the polyester diol, polyisocyanate, olefinically unsaturated monomer and the respective catalysts as described and claimed herein.
U.S. Pat. No. 3,723,370 relates to urethanated unsaturated polyester resins prepared by mixing and reacting an olefinically unsaturated polyester resin, an olefinically unsaturated monomer, e.g., styrene and a polyisocyanate. The patent cautions that when the ratio of polyhydric alcohol to polycarboxylic acid is more than 1.7, it is difficult to obtain a suitable unsaturated polyester. In addition, the patent fails to disclose or suggest unsaturated polyester polyols having acid numbers below 3.
U.S. Pat. No. 3,776,980 discloses the preparation of olefinically unsaturated polyesters having high acid numbers and fails to disclose or suggest the use of the glycol mixtures disclosed in the present invention.
There are many other patents and publications directed to olefinically unsaturated polyesters in addition to those specified above. However, these additional patents and publications fail to disclose or suggest olefinically unsaturated polyester polyols having acid numbers below 3 and made from glycols and polycarboxylic acids in glycol-to-acid mole ratio of 1.75 or more. Included in such patents and publications are German Publication No. 2,300,372, laid open to the public July 12, 1973, Canadian Pat. No. 460,392, Japanese Publication No. JA 4785, published May 9, 1960 and U.S. Pat. Nos. 2,255,313; 2,553,325; 2,642,410; 2,642,403; 2,643,985; 2,780,613; 2,840,538; 2,888,433; 2,892,812; 2,892,813; 3,007,894; 3,008,917; 3,109,833; 3,340,083; 3,345,339; 3,355,408; 3,371,056; 3,597,495; 3,652,470; 3,882,189; 3,901,953; 3,911,048; 3,911,050; 3,923,927; 4,006,272; 4,036,908; 4,098,733; 4,158,027.